I don't know where else to go. A group of pretty smart "lighting guys" are trying to grow algae with LED lights. The problem is LED's specific and narrow color range.Here is our method.

Tank with livestock(fish)The water system for the fish feeds the water into a large pipe with a slit cut down the middle. So if the pipe is 3ft long it has a 1/8th" slit.hanging from the pipe..and partially inside the slit. water runs out the slit down a rough canvas say 3ft wide hanging down 10ft. lighting is provided on each side of the canvas. On this canvas obviously the algea grows. then the water is pumped back into the fish tank. The algae grows rapidly and while doing so oxgenates and filters the bad stuff out of the water for the fish.

This all works fantasticly for the algae growing and for the fish farming(win win). Just feed the fish and turn the lights for the algae on 16hrs/day.

Currently flourecent lights are being used(aprox 20w per square foot).The main objective is filitering the water for the fish not so much for growing the algea..its all currently getting tossed out(about a tennis ball size solid clump per square foot per couple days). I don't know if thats efficent enough for sole biofuel use but could be a side benefit for fish farming.

We are looking for way to decrease the energy use on the lighting and/or speed up the algea growth via light. Our problem is the flourecent lights work great..however we are having problems getting the LED's to work. We assume it has to do with the narrow spectrum the tend to occupy.

If we are using LED light can anyone say exactly what nm color and in what ratio is best for growing algae with LED light?

It can depend upon what species of algae you are growing, but generally speaking, the strongest absorption peak for chlorophyll 'a' is in the deep blue, followed by deep red. (BTW, don't let the misplaced color spread in the picture throw you off, despite what it shows, it's 430-460nm blue, and 660-700nm red).For your purposes, you can practically ignore the chlorphyll 'b' line, since there are only about 1/3 as many 'b' receptors as 'a', and because the chlorophyll 'b' is (considered to be) an "accessory" pigment that transfers the light it absorbs to chlorophyll 'a'.And DO ignore the wavelengths that are closer to the baseline between deep blue and deep red peaks, because they are so inefficiently absorbed that you'll waste most of the power used to develop the light. Good luck, and happy algae growing.

Well, try the blue led bulb light or even the red. But I don’t know the exact combination of the two colors in growing the algae. I’m using the blue led light bulb for my tank and so far I don’t have any problem regarding in growing the algae.